Ed might be right but I got it from Vox Day who as you know is the head of the Rabid Puppies.

Most of the Alt-Right picked up the terminology of the God Emperor of the Cherry Blossom Throne as it annoys the crap out of the Never Trumpers. A spoof on their claim that he is worshiped like a god by his fans.

The term God Emperor as ed has stated is from how the Japanese characterized their emperor. Also, in sci-fi lore, there is a milieu called Warhammer 40k which is set in a future earth 40,000 years from now, humanity has colonized the known universe, but is in a constant state of warfare with other species. It's also a role-playing game. The leader of this sci-fi fictional universe is only known as The God Emperor. No one utters his name.